$\frac{4}{7}x+\frac{5}{14}x=39$

$y=x^2-2x^{-1}$

$restar\:\frac{7}{3}a+\frac{5}{4}bc-\frac{7}{9}xy^2-\frac{9}{3}a^2de\frac{1}{5}a+\frac{7}{9}bc-\frac{4}{8}yx^2-\frac{7}{5}a^3$

$9x^2+21x-30$

$-x^3+x^2+8x-12$

$\lim_{x\to\infty}\left(\frac{5x\:+\:2\ln\left(x\right)}{x+3\ln\left(x\right)}\right)$

$\left(6a-4b+2\right)^2$